The setting of blind rivet elements and the special riveting tools to be employed for this purpose are described, for example, in DE 10 2013 105 703 A1. In order to set the blind rivet element, the blind rivet element is inserted into a riveting tool so that, using the mandrel to which the rivet element is screwed, the rivet element is subjected in a pulling movement to an axially attacking force. The rivet element is forcibly plastically deformed via the axial force to accomplish a form-locked connection of the rivet element with the workpiece. An interaction is required between the axial movement of the mandrel and the rivet element connected thereto, and a mouthpiece in order to achieve the deformation of the rivet element. The mouthpiece is arranged relative to the mandrel so that the movement of the rivet element is one-sidedly restricted by the mouthpiece and the rivet element is forced into a plastic deformation by driving the mandrel further in.
As part of this process, the blind rivet element is initially screwed onto the mandrel when the mandrel is in a front end position. The mandrel is then shifted by an axial movement into the rear end position in which the blind rivet element is in contact with the mouthpiece.
In order to find the most suitable set-up for the optimal setting and the shortest time cycle of a rivet element, it has to date been necessary to adjust the position of the mouthpiece relative to the mandrel in the rear end position to match the length of the type of rivet element used by screwing and unscrewing the mouthpiece. In order to correctly configure the riveting tool, it has therefore been necessary to perform the following working steps:                fitting a suitable mandrel and a mouthpiece onto the riveting tool;        screwing a blind rivet element onto the mandrel to an extent where the thread reaches its full bearing power;        adjusting the mouthpiece so that it makes contact with the head of the blind rivet element; and        setting the blind rivet element into the workpiece and then undoing the screw connection of the rivet element.        
A correct configuration of the setting tool, in particular a correct adjustment of the mouthpiece relative to the mandrel in the rear end position and in dependence of the type of blind rivet element used, is important to correctly set the rivet element. An incorrect set-up may lead to the rivet element not being fixed in its position with optimum stability. If the thread of the rivet element is not screwed far enough into the mouthpiece, or in other words, if the thread of the rivet element contacts the mouthpiece before the thread has reached its full bearing power, the thread of the rivet element may be damaged or be torn out. Valuable time is lost in the working cycle if the mandrel is screwed in too far. Both these factors must be avoided.
Setting tools according to the prior art only consider these facts to the extent that they rely on the “finger-tip” skill of the user. The quality of the setting job is therefore essentially dependent on the skill of the user. Adjustment of the mouthpiece, especially when using several different types of blind rivet element, is also a job which requires a considerable amount of time.